01 - Rinse sushi rice under cold running water, gently agitating with your hands until the water runs completely clear. Combine drained rice and water in a medium saucepan. Bring to a rolling boil over high heat, immediately reduce to low, cover tightly, and simmer for 15 minutes until water is absorbed. Remove from heat and let stand, covered, for an additional 10 minutes. Meanwhile, dissolve sugar and salt in warm rice vinegar. Fluff cooked rice with a wooden paddle or fork, then gradually fold in the vinegar mixture while fanning to cool. Spread rice on a baking sheet and bring to room temperature before assembling.
02 - While rice cools, slice prosciutto into manageable strips if needed. Cut fresh mozzarella into uniform thin strips approximately ¼ inch wide. Slice roasted red bell peppers into thin matchsticks. Drain sun-dried tomatoes well and julienne into thin strips. Pick fresh basil leaves, discarding stems. Wash and gently pat arugula leaves dry. Keep all prepared ingredients separated on a cutting board or tray for easy assembly.
03 - Place a nori sheet on a bamboo sushi rolling mat with the shiny side facing down. Lightly moisten your hands with water to prevent sticking. Grab approximately ¾ cup of seasoned rice and spread it evenly over the nori, leaving a 1-inch empty border at the top edge. Arrange prosciutto slices first, then layer mozzarella strips, roasted peppers, sun-dried tomatoes, arugula leaves, and fresh basil in a horizontal line across the bottom third of the rice. Drizzle with ½ teaspoon olive oil and season with freshly ground black pepper.
04 - Using the bamboo mat, lift the edge closest to you and roll forward, applying gentle but firm pressure to create a tight cylinder. Seal the roll by moistening the exposed nori edge with water and pressing firmly. Repeat with remaining ingredients to form 4 rolls total. Using a sharp knife dampened with water, slice each roll into 6 equal pieces, wiping the blade clean between cuts for neat presentation.
05 - Arrange sliced sushi pieces on a serving platter, presentation-side up. Optionally drizzle with balsamic glaze in a decorative pattern and garnish with additional fresh basil leaves. Serve immediately at room temperature for optimal texture and flavor. Do not refrigerate after assembly as rice will harden.